Generating energy from natural sources, such as sun and wind, has been an important objective in this country over the last several decades. Reducing reliance on oil, such as from foreign sources, has become an important national issue. Energy experts fear that these resources, including oil, gas and coal, will someday run out. Because of these concerns, many projects have been initiated in an attempt to harness energy derived from what are often called natural “alternative” sources.
Wind farms, for example, have been built in areas where the wind naturally blows. In many areas, a large number of wind turbines are built and “aimed” toward the wind, wherein rotational power is created and used to drive generators, which in turn, generate electricity. Wind farms are most efficiently operated when wind conditions are relatively constant and predictable. Such conditions enable the supply and delivery of energy generated by the wind to be consistent, thereby avoiding surges and swings that can adversely affect the system. Failure to properly account for these conditions can result in power outages and failures, wherein a failure in one area of the grid could cause the entire system to fail, i.e., an entire regional blackout can occur.
The difficulty of operating wind farms, however, is that wind by its very nature is inconsistent and unpredictable. In many cases, wind speeds, frequencies, and durations vary considerably, i.e., the wind never blows at the same speed over a period of time, and wind speeds can vary significantly from one moment to another. And, because the amount of power generated by wind is mathematically a function of the cube of the wind speed, even the slightest fluctuation or oscillation in wind speed can result in a disproportionate change in wind-generated power.
These conditions can lead to problems. For example, in the context of a wind farm delivering energy to an electrical power grid, which is a giant network composed of a multitude of smaller networks, these sudden surges in one area can upset other areas and can even bring down the entire system in some cases. Also, if a wind farm is dedicated to providing energy to a community or facility, the same surges can cause overloads that can damage components connected to the system.
Another problem associated with wind fluctuations and oscillations relates to the peak power sensitivity of the transmission lines. When wind speed fluctuations are significant, and substantial wind power output fluctuations occur, the system must be designed with enough line capacity to withstand these occurrences. At the same time, if too much consideration is given to peak power outputs, the system could be over-designed, in which case, during normal operating conditions, the system may not operate efficiently, thereby increasing the cost of energy.
Another related problem is the temporary loss of wind power associated with an absence of wind or very low wind speed in some circumstances. When this occurs, there may be a gap in wind power supply, which can be detrimental to the overall grid power output. This is especially important during high demand periods, such as during periods when heating and cooling requirements are normally high.
Because of these problems, attempts have been made in the past to store energy produced by the wind so that wind generated energy can be used during peak demand periods, and/or periods when little or no wind is available. Utility companies and other providers of energy have, in the past, implemented certain time-shifting methods, wherein energy available during low demand periods is stored, and then used later during peak demand periods. These methods typically involve storing energy, and then using that energy later, to supplement the energy that is otherwise available.
Several such energy storage methods have been used in the past, including compressed air energy storage systems, such as underground caverns and tanks. Thus far, however, one of the main disadvantages of such systems is that they are relatively energy inefficient. For example, compressed air energy systems have a tendency to lose a significant portion of the stored energy when converting the compressed air energy to electrical energy, wherein the energy used from storage ends up costing more than the energy that was stored, i.e., just converting compressed air energy into electrical energy often results in a substantial loss of energy. These inefficiencies can make it so that the economic incentives required to install energy storage systems of this kind are significantly reduced. Past systems have not been able to reduce the inefficiencies, as well as the fluctuation and oscillation problems discussed above, inherent in using wind as an energy source.
Another problem associated with wind energy is that even if wind farms are located where the wind is more predictable and constant, and, even if storage facilities are constructed, there is the additional problem of getting the energy to where the energy is needed. In many cases, wind farms are located far from existing power grids, and far from communities and facilities where energy is needed, i.e., the ideal location for a wind farm may be on top of a hill, or mountain, or in a canyon, or the desert, or somewhere offshore, etc., which can be many miles from the site that needs the power. In such case, it would be extremely expensive to build power transmission lines to transmit electrical power generated by the wind farm, just to service the wind farm. Not only could there be significant costs associated with building storage tanks, i.e., to store energy as discussed above, but there would be an even greater cost associated with constructing new transmission lines that will have to extend great distances. Right-of-way costs will also be incurred, i.e., it is often necessary to obtain permission from local communities, wherein the process of obtaining approval can be time consuming and costly.
When conventional power transmission lines are involved, and used to transmit energy over long distances, there is the additional problem of line losses. This has become an increasing problem throughout the country. For example, despite the many thousands of miles of high voltage electric transmission lines that have been built over the last few decades, the rate of building new transmission lines has actually decreased, while the demand for electricity has continued to increase. In fact, according to some statistics, annual investment in new transmission facilities has declined over the last 25 years, wherein the result has been excess grid congestion, and bottlenecking, which has led to higher electricity costs, i.e., due to the inability of customers to access lower-cost electricity supplies, and because of higher line losses.
Line losses are often related to how heavily the system is loaded, and inherent to wiring properties and conditions used to transmit the energy. In fact, transmission and distribution losses were at about 5% in 1970, but have increased to about 9.5% in 2001, due to increased energy demand without an adequate increase in transmission facilities. These losses are caused by congested transmission paths that can affect various aspects of the grid, wherein it is estimated that power outages and quality disturbances have cost the economy up to $180 billion annually.
Another related problem is that throughout the country, the highest demand for energy often occurs during the day, and therefore, the demand for electrical energy during the most high-demand period continues to increase. These peak demands can place a heavy burden on utility plants and grids that supply electrical power, wherein they often have to be constructed to meet the highest demand periods, which means that during the low demand periods, they will inevitably operate inefficiently, i.e., at less than peak efficiency and performance. This means that not only must the transmission lines be built to withstand the highest demand periods, but the utility plants themselves must be designed to generate enough energy during the peak demand periods, even if those periods only occur during a small fraction of the time each month. This is because the transmission lines themselves do not store energy, i.e., they are merely energy “conduits,” and therefore, the utility plants must be able to produce and supply the higher amounts of energy. Failure to properly account for such high demand periods, such as by over-designing the facilities to meet the peak demands, can result in the occurrence of frequent power outages and failures, and increased costs.
These demands can also place expensive burdens on customers that need to use energy during the peak demand periods, including many commercial and industrial property owners and operators. Utility companies often charge a significant premium on energy consumed during peak demand periods. This practice is generally based on the well known principles of supply and demand, e.g., energy costs are higher when demand is high, and less when demand is low. And because most commercial and industrial property owners are forced to operate during the day, they are most often forced to pay the highest energy costs during the highest demand periods.
Utility companies also charge for peak power usage during peak demand periods by assessing a penalty or surcharge (hereinafter “demand charge”) on the maximum rate of consumption of power that occurs during a predetermined period, such as during a one month period. A demand charge may be assessed, for example, based on the maximum “peak” rate of consumption that occurs during a short spike or surge, wherein the demand charge can be assessed regardless of how short the “spike” or “surge” might be during that period, and regardless of what rate may apply immediately before and after the spike or surge. This demand charge can also be assessed regardless of the average consumption rate that may have been in effect during the period, which could be considerably lower than the peak. Even if the overall average rate of use is substantially lower, the demand charge can be based on a much higher spike or surge, experienced for a very short time during that period.
These pricing practices are designed to help utility companies offset and/or recover the high cost of constructing utility power plants and grids that are, as discussed above, designed to meet the peak demand periods. They also encourage commercial and industrial property owners and operators to reduce energy consumption during peak periods, as well as to try to find alternative sources of energy, if possible. Nevertheless, since most commercial and industrial property owners and operators must operate their businesses during the day, and alternative sources of energy are not always readily available, they often find themselves having to use energy from the grid during the highest rate periods. Moreover, because energy consumption rates can fluctuate, and surges and spikes can occur at various times, potentially huge demand charges may be applied.